Numerous types of implantable medical devices (IMDs) are available for monitoring a patient and/or delivering automatic therapies, such as ECG monitors, cardiac monitors, pacemakers, defibrillators, drug delivery pumps, neurostimulators and the like. A general design goal in the manufacture of IMDs is to provide a smooth, rounded shape and minimal size of the IMD to promote patient comfort. Additionally, it is desirable to minimize the cost and complexity of manufacturing steps used in producing IMDs.
The outer housing of the IMD encloses electronics that perform the various IMD functions such as acquiring and analyzing physiological signals, automatically delivering therapies, and wirelessly communicating with an external programmer or other device. The housing reliably shields internal electronics that could be damaged or malfunction if exposed to body fluids.
In some medical applications, the IMD placement at an implant site or “pocket” is critical to proper functioning for sensing physiological signals and/or delivering effective therapies. For example, an implantable cardioverter defibrillator (ICD) that delivers defibrillation shocks to the heart using subcutaneous electrodes and the ICD housing or can electrode may be implanted to achieve a desired shock vector through the heart. Migration of the ICD may compromise the efficacy of the defibrillation shocks or increase the shock energy required to effectively defibrillate the heart.